Construction Machine, In Particular Rubber-Tired Roller Or Road Finisher

ABSTRACT

The present invention relates to a construction machine, said construction machine comprising a brake assembly for braking the machine, as well as an operator platform. The operator platform comprises at least one operator seat with a total of at least two operating positions for a machine operator at opposite ends of the operator platform, and an actuation device for foot actuation of the brake assembly. According to essential aspects of the present invention, the actuation device for the brake assembly comprises a brake beam which extends transversely to the working direction of the construction machine and which can be operated by foot from said two operating positions, and the actuation device further comprises an actuator for the brake beam, which is arranged below the brake beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 of GermanPatent Application No. 10 2015 012 666.0, filed Sep. 30, 2015, thedisclosure of which is hereby incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates to self-propelled construction machinesfor soil compaction such as tandem rollers usually moved at comparablylow speeds during driving operation.

BACKGROUND OF THE INVENTION

By way of example, reference shall be made to the BOMAG BW 206 AD-5 AMmodel of the same Applicant, which has a maximum speed of approximately12 km/h. This is also why generally the maximum brake effect required tobring such a construction machine to a halt is comparatively low despitethe high weight of these construction machines. This is why constructionmachines of the above type are often times sufficiently braked by merelyone hydrostatic brake assembly. The advantage of a hydrostatic brakeassembly lies with the fact that it is particularly suitable for arecuperative braking process in which the kinetic energy lost throughthe braking process can be used again. Corresponding brake assembliesare known, for example, from prior art publications DE 10 2006 050 873A1 and DE 10 2006 060 014 A1. Inter alia, one specific feature ofhydrostatic brake assemblies is that they do not require separateactuation by the machine operator in addition to speed regulation.

However, some of the construction machines of the above type, inparticular rubber-tired rollers, have a significantly higher maximumspeed and may reach up to 20 km/h. A rubber-tired roller is described inDE 11 2011 104 404 T5, for example. The braking effect of one singlehydrostatic brake assembly is not sufficient for such machines in orderto bring the construction machine to a halt within a satisfactory timeperiod. Accordingly, it is desirable to have an additional brakeassembly. However, in contrast to hydrostatic brake systems, such brakeassemblies need to be operated by the machine operator explicitly orseparately from speed regulation for triggering a braking process. Thus,an actuation device is required via which the brake assembly can beoperated by the machine operator. This poses a challenge with regard tothe construction of such machines since the operating position of theoperator within the operator cabin is oftentimes variable, “variable” inthis context not relating to a minimal seat adjustment for considerationof different body sizes, but to various specific operating positions onthe operator platform as, for example, alternatively on the right or onthe left side. Operator platforms that include multiple operator seatsin different positions at the same time are known from the prior art. Asan alternative, seat assemblies are known in which an individualoperator seat may take different positions on the platform by displacingor rotating said seat. For example, this may be effected by means ofsuitable rail systems, pivoting arms or pivoting and/or shiftingconsoles. In particular, in such cases it is known to provide theactuation elements, such as in particular the brake pedal, either inmultiple form in the operator platform or to carry them along with theoperator seat in a comparatively elaborate fashion, requiringconsiderable effort for the guidance of hydraulic tubes and/or electricsignal lines. The known solutions are thus comparatively complicated andsometimes lead to undesirable redundancy and parallel architectures,respectively, resulting also in higher production and maintenance costs.

SUMMARY OF THE INVENTION

Thus, a principle of the present invention is to provide an actuationdevice for the brake assembly of a construction machine of the aforesaidtype, which particularly comprises an operator platform with differentoperating positions and which has a simple structure and, at the sametime, can be operated flexibly from different positions.

Specifically, the principle of the present invention is achieved by aconstruction machine which comprises a brake assembly for braking theconstruction machine and an operator platform. The operator platformcomprises at least one operator seat with a total of at least two sideoperating positions for a machine operator. A “side operating position”specifically relates to a position of the operator seat on a side of theconstruction machine, i.e., the operator seat is positioned on the rightor on the left-hand side on the operator platform when viewed in theworking direction. The machine operator on the operator platform maythus view the side of the machine or view along the side of a machinefrom the respective side operating position. The present invention alsocomprises the option of fine-adjustment of the operator seat in therespective side operating position in order to enable adjustment of theseat position to various body sizes, for example. However, said regularseat adjustment when in a certain side operating position is explicitlynot comprised in the adjustment of the entire operator seat to variousside operating positions. The side operating positions are preferablylocated at opposite ends of the operator platform, for example, on theright-hand side of the operator platform and on the left-hand side ofthe operator platform with respect to the working direction or forwarddirection of the construction machine. Furthermore, the operatorplatform comprises an actuation device for foot actuation of the firstbrake assembly. Thus, the actuation device can be actuated by means of afoot movement by the operator seated on the operator seat.

One aspect of the present invention is to configure the actuation devicefor the brake assembly with a brake beam, said break beam extendingtransversely to the working direction of the construction machine on theoperator platform in such a way that it can be operated by foot, inparticular pressed, from the at least two side operating positions. Thebrake beam according to one embodiment of the present invention thusrefers to a longitudinally extending operating element whichlongitudinally extends on the operator platform in particulartransversely to the working direction in such a way that it can bereached by an operator seated in the operator seat from variouspositions of the operator seat and ideally across the entire adjustmentrange of the operator seat and can be actuated by foot for triggering abraking operation. Basically, the brake beam functions as a transferringelement from the driver to an actuator of the actuation device, theactuator being arranged below the brake beam. As a result, on the onehand, carrying along the brake pedal upon seat adjustment betweenvarious side operating positions may be omitted, resulting in aconsiderably smaller construction effort. On the other hand, only onesingle actuator adapted for receiving and transmitting the brakingsignal is required since the machine operator can trigger the brakingsignal from various side operating positions centrally via one singlebrake beam. Accordingly, the specific construction of the brake beam isachieved in a simple and cost-effective manner.

Realization in practice has shown that it is particularly favorable forthe brake beam to extend continuously across at least 65% and, moreparticularly, across at least 80% of the width of the base area of theoperator platform, specifically arranged centrally in relation to thelongitudinal center line in the working direction. Here, continuouslymeans that the brake beam is configured such that it can be actuatedacross its entire length. Thus, the brake beam is continuous even if itcomprises perforations or comparable structures, provided this does notobstruct continuous operability, in particular operation by foot. Therelevant width of the base area depends on the arrangement of the brakebeam. If the brake beam extends transversely to the working directionthrough the operator platform, the width of the operator platform or inparticular the width of the floor of said platform is relevant here,more particularly the floor area in which the two side operatingpositions of the operator seat are located or in which the brake beam isarranged on the floor in a position that can be reached from theoperator seat.

According to one embodiment of the present invention, a surface of thebrake beam facing the operator seat corresponding to the step area ofthe brake beam is designed as a continuous actuation surface, inparticular closed to the outside. This configuration is advantageous asit prevents or at least reduces the ingress of dirt into the regionbelow the brake beam. It is particularly preferred here for theactuation surface to have an anti-slip coating so that the risk of themachine operator slipping-off with the foot and not being capable ofproperly controlling the braking operation is reduced. Such an anti-slipcoating may be a roughened or an otherwise appropriately structuredsurface of a known type. In particular for production-related reasons, arectangular design of the actuation surface and/or a cuboid design ofthe brake beam have proven to be advantageous.

The specific mounting of the brake beam may vary. For example, it ispossible to mount the brake beam in its edge regions or directly andexclusively on an actuator. Mounting of the brake beam for an operatorplatform with a platform floor can be achieved in a particularlycost-effective manner which is also suitable for retrofitting if thebrake beam is pivotally mounted via a joint, in particular a hinge,preferably directly, on the operator platform base. In order to allowfor a particularly safe mounting, it is preferred in light of thelongitudinal extension of the brake beam to not exclusively mount thebrake beam via a single joint, in particular a hinge, but a plurality ofjoints/hinges, in particular three or more, which are preferablydistributed at regular intervals in the direction of the longitudinalextension of the brake beam. This allows a particularly robust and safemounting of the brake beam. It is particularly preferred for the brakebeam to be mounted with an edge facing the operator seat via thejoints/hinges on the platform base such that it can be easily pivoteddownward away from the driver. This way, actuation by foot is possiblein a particularly preferred manner.

According to another embodiment, the actuation device comprises a jointprotection, particularly a hinge protection. Said protection is arrangedabove the joint/hinge and in particular configured as a chamferedprotection strip along the entire edge of the brake beam facing theoperator seat. The risk of the joint/hinge being damaged or impaired,for example, caused by the operating behavior of the machine operator orby sand or dirt carried onto the operator platform by the machineoperator can be reduced by means of the joint/hinge protection. Thisresults in a considerably reduced maintenance effort for thejoint/hinge, for example.

According to another embodiment of the present invention, an edge of thebrake beam facing away from the operator seat is chamfered relative tothe step area of the brake beam, especially bent downwards. Inparticular, said edge is bent to the inside downwards twice at a rightangle so that the double-bent part of the edge forms a support surfacein the form of a U-shaped profile for the brake beam. This way, the edgefacing away from the operator seat may form a stop, for example, bymeans of which the brake beam may rest on the operator platform base,without the entire lower side of the brake beam being parallel to theoperator platform base. This way, the brake beam, in particular theactuation surface, can maintain a certain inclination relative to theoperator platform floor also in a fully actuated position, in particularin a range of bigger than 0° to 20° so that an ergonomically morefavorable foot position for the machine operator is enabled even whenthe brake beam is actuated or pushed down.

Transmission of the beam position to a brake actuator is basicallyeffected indirectly or directly via the brake beam. Now, it is ideal inthis case if a transmission mechanism for the actuator is completelycovered upwards by means of the brake beam and the operator platformbase. This way, a hollow space for the transmission mechanism and theactuator is obtained, which space is more or less shielded relative tothe inside of the operator platform, in particular in connection withthe aforementioned joints/hinges and the protection strip.

The brake beam is preferably spring-loaded, particularly in directiontowards an end position in which no braking actuation is triggered. Thespring load may be designed such that it acts directly on the brakebeam. Thus, a return spring is articulated on the brake beam. However,return of the brake beam is preferably effected by means of aspring-loaded actuator. Here, the actuator is loaded with the returndevice in such a way that upon non-actuation of the brake beam said beamis automatically returned to a resting position, i.e., a position nottriggering a braking effect. To this end, the return device is inparticular arranged below the brake beam. With regard to reliability, itis particularly advantageous if the return device comprises multiplereturn springs which are in particular arranged to act parallel to oneanother. The present invention generally also covers such embodiments inwhich the return spring is replaced by another elastic component, suchas a rubber buffer, for example. The embodiment mentioned is basicallycharacterized by the fact that the automatic return of the brake beaminto its resting position is ensured.

As the brake is an essential component with respect to the operationalsafety of a construction machine, it must be ensured that said brake canbe actuated reliably during operation. As a safety measure, it is, inparticular, provided to that end that the brake beam automatically sinksdownward due to its own weight upon breaking of the return spring, thuspermanently actuating the actuator. A braking action is triggeredthereby and the construction machine is stopped. Another safety measuremay consist in that the actuation device comprises a spring breaksensor. Said sensor in particular serves for detecting a spring break ofthe return spring of the brake beam. This way, operational safety of thebrake beam can be enhanced since damage of the return spring may bedetected and an emergency stop of the machine may be initiated in thecase that the detector detects a spring break. The spring break sensormay be arranged below the brake beam, for example. Regardless of the useof the return spring, devices ensuring functionality of the actuationdevice are generally preferably integrated in the actuation device.

For specific implementation of the present invention according to oneembodiment, is has proven to be advantageous that the actuator isarranged centrally relative to the brake beam, in particular withrespect to its longitudinal extension. Specifically, this centralarrangement relates to the extension of the brake beam along alongitudinal central axis of the brake beam. In relation to the workingdirection of the construction machine, the longitudinal central axis ofthe brake beam thus preferably extends horizontally and essentiallyperpendicular to the working direction. Central arrangement of theactuator on the brake beam can ensure a most uniform operating behaviorof the brake beam across the entire width of the brake beam.

Furthermore, the actuator may directly be connected to the brake beam.However, an arrangement of the actuator relative to the brake beam insuch a way that said brake beam rests on the actuator and the twocomponents move relative to one another upon actuation of the brake beamis preferred, with the two components remaining in direct contact. Inorder to reduce frictional forces here, a contact roller is arranged onthe actuator, via which roller the brake beam rests on the actuator. Thelower side of the brake beam directly forms a rolling surface for thecontact roller. This way, inclination of the brake beam may betransferred into a movement of the actuator.

For the specific design of the actuator, the actuators known from priorart can basically be used. An actuator configured as brake pedal,comprising a lever element rotatable about an axis, is particularlysuitable to that end. The actuator actuated by the brake beam ispreferably connected to an electric, hydraulic or pneumatic brake valveeither in mechanical or electrical manner. By means of such a brakevalve, a braking operation can be initiated for the braking assembly ina manner known in the prior art.

Furthermore, it is preferred in one embodiment for the actuation deviceto include a side protection, which side protection is arranged on aside of the break beam facing away from the operator seat and which isdesigned to seal a hollow space below the brake beam relative to saidside. Here, the side of the brake beam facing away from the operatorseat is in particular a face side of the brake beam and essentiallyextends in parallel to the working direction of the construction machinein its extension plane. This way, parts of the actuation device arrangedin the hollow space below the brake beam, such as the actuator, forexample, are protected against dirt and unintentional impairment by themachine operator also from this side. The side protection may bedesigned integrally with the actuation surface of the brake beam.

According to another embodiment of the present invention, the actuationdevice comprises a rotation angle sensor which is arranged below thebrake beam or below the platform base. Said rotation angle sensor isdesigned to determine a rotation angle of the brake beam. Here,determination of the rotation angle can be effected directly, but, inparticular, it is effected indirectly, by measuring an angle resultingfrom a mechanical transmission of the movement of the brake beam, fromwhich the rotation angle of the brake beam can subsequently bedetermined using a known calculation rule. Also, the rotation anglesensor may be connected to an electronic control unit of theconstruction machine, such that data derived by the rotation anglesensor for rotating the brake beam may as well be used with controlprograms of the construction machine.

According to another embodiment of the present invention, the operatorseat comprises at least one of the following features: The operator seatis configured as a rotatable operator seat, in particular about avertical rotation axis, the operator seat is configured as a laterallydisplaceable operator seat, the operator seat is arranged on a laterallydisplaceable seat support or the operator seat is arranged relative tothe brake beam in such a way that the brake beam is located within thecomfort region of the seated machine operator, said region defined bythe DIN EN ISO 6682:2009-06 standard for foot-actuatable controls inearth moving machines. In other words, it is an essential idea of thepresent invention that the operator seat is most flexible inpositioning, such that only one operator seat which can particularly beadjusted between the side operating positions is required and a secondoperator seat can be dispensed with.

Furthermore, with respect to the design of the operator platform, thepresent invention can be combined with the systems disclosed inpublications DE 10 2010 035 270 A1 and DE 10 2007 018 744 A1, which arehereby incorporated herein by reference.

The above-described brake assembly according to the present invention ispreferably part of a larger brake system of the construction machine.The brake assembly according to the present invention is configured asoperating brake here, in particular acting as a disc brake, drum brakeor multi-disc brake. To that end, the brake system comprises a secondbrake assembly, which brake assembly is designed in particular as ahydrostatic brake assembly. Preferably, the braking effect of the brakeassembly and the braking effect of the second brake assembly can becombined into a joint braking effect by means of the brake system. Thiscan be effected in a way basically known by a person of ordinary skillin the art.

The brake assembly according to the present invention is particularlysuitable for construction machines, in particular for road finishers orsoil compactors, in particular rubber-tired rollers. Said constructionmachines require frequent braking operations on the one hand and regularoperations from different sides of the operator platform on the otherhand.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in more detail below by means of theexemplary embodiments indicated in the figures. In the schematicfigures:

FIG. 1a shows a side view of a rubber-tired roller;

FIG. 1b shows a side view of a road finisher;

FIG. 2 shows a perspective view of the operator platform of aconstruction machine according to the present invention;

FIGS. 3a to 3c show in each case a plan view of the operator platform ofa construction machine according to the present invention with anoperator seat in different positions;

FIG. 4 shows a side view of the operator platform of a constructionmachine according to the present invention with non-actuated brake beam,the area of the brake beam and the actuator being particularlyhighlighted;

FIG. 5 shows a side view of the operator platform of a constructionmachine according to the present invention with the actuated brake beam,the area of the brake beam and the actuator being particularlyhighlighted; and

FIG. 6 shows a perspective view of the lower side of the actuationdevice of a construction machine according to the present invention, thearea of the brake beam and the actuator being particularly highlighted.

Like components are indicated with like reference numerals throughoutthe drawings, however not every repeating component is necessarilyindicated separately in each drawing.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1a is a side view of a construction machine 1, in particular arubber-tired roller. Construction machine 1 comprises a machine frame 2and two running gears 3, each having multiple rubber tires forcompacting the underlying soil. At the same time, said running gears 3serve for moving the construction machine 1. During working operation,the construction machine travels in the working direction a using therunning gears 3, thereby compacting the underground by acting on thelatter with its operating weight via the rubber tires. Furthermore, anoperator platform 4 for the machine operator is provided for operatingthe construction machine 1, the platform comprising an operating console5 and an operator seat 6.

FIG. 1b illustrates the general configuration of another constructionmachine 1 which is particularly suitable for being used in the presentinvention. In particular, said machine is a road finisher likewisecomprising an operator platform 4, on which an operating console 5 andan operator seat 6 are arranged for operating the machine. The roadfinisher comprises multiple tires 3 as a moving device, although it isalso possible to use crawler tracks here.

Both construction machines 1 shown in FIGS. 1a and 1b have in commonthat the operator located on the operator platform 4 often needs to vieweither the left side or the right side of the machine depending on thecurrent working situation, for example, when driving the machine alongedges or other obstacles. To that end, the operator seat 6 is arrangedsuch that it can be adjusted from a right side operating position, inwhich the driver is capable of viewing the right machine side, to a leftside operating position, in which the driver is capable of viewing theleft machine side. A device that enables such adjustability isdisclosed, for example, in patent specifications DE 10 2010 035 270 A1and DE 10 2007 018 744 A1 of the same Applicant, which are herebyincorporated herein by referenced.

The following figures explain further details on the configuration ofthe operator platform and functionality of the present invention.

First, an overview of the specific configuration of the operatorplatform 4 in a perspective view can be taken form FIG. 2. The operatorseat 6 is arranged on a seat support 22 which is designed to have asupport for the operator console 5 arranged opposite the operator seat6. The seat support 22 enables moving the operator seat 6 and theoperator console 5 together along a guide rail 7 back and forth betweenthe outer sides of the operator platform 4 in a parallel, sled-likemanner transversely to the working direction or forward direction A ofthe construction machine 1. In addition to said adjustment of the seatposition, the operator seat 6 can be fine-adjusted on the seat support22, for example, in terms of height, front-back-position and sideposition. However, this adjustment allows adjusting the seat within therange of a few centimeters only, whereas adjustment via the guide railenables adjustment across the entire width 8 of the operator platform orthe platform base 8, respectively. The platform base 8 forms the bottomboundary of the platform 44.

The brake beam 10 is arranged on the operator platform 8 opposite theoperator seat 6 and is comfortably reachable by foot for the machineoperator, the brake beam 10 being part of an actuation device 9 foractuating a brake assembly of the construction machine 1. The brake beam10 is supported on the platform base 8 by multiple joints, in particularrotary joints, in the present exemplary embodiment, for example, bymeans of parallel arranged hinges 13, on the side facing the operatorseat 6 in such a way that it can be pivoted along said hinges 13 with adegree of freedom about an axis oriented horizontally and transverselyto the working direction. In other words, the brake beam 10 can befolded up and down along the hinges 13. The brake beam 10 can be pivotedalong the hinges 13 between an entirely operated position and a restposition, the rest position and the entirely operated position eachbeing defined by a stop of the brake beam 10.

Furthermore, a surface of the brake beam 10 facing the operator seat 6is configured as an actuation surface 23. Actuation of the brake beam 10is effected in such a way that the machine operator acts on the brakebeam 10 by foot, as a result of which the brake beam folds downwardabout pivot axes of the hinges 13 as a result. Said hinges 13 are alsolocated in the region provided for foot actuation by the machineoperator. For this reason, the brake beam 10 terminates toward theoperator side by means of a joint or hinge protection, which is in thepresent case configured as a chamfered protection strip 11. Saidprotection strip 11 covers the hinges 13 and thus protects them againstmechanical damages by the machine operator as well as againstcontamination. The actuation device 9 in each case terminates with aside protection 12 toward the sides of the operator platform 4, saidside protection 12 delimiting a hollow space 20 below the brake beam 10sideward. This way, the side protection 12 also serves for protectingthe actuation device 9 overall against ingress of dirt or unintentionalmechanical damage. This is relevant particularly because the actuator 15for the brake beam 10 is also arranged in the hollow space 20 below thebrake beam 10, and is thus also protected. However, said hollow space 20and actuator 15 are not shown in FIG. 2 as they are covered by the brakebeam 10 in this view. In the present exemplary embodiment, the sideprotection 12 is a protection plate 12 protruding from the platformbase, although it is also possible and covered by the present inventionto consider other alternatives such as protection mats, bellows, etc.The essential factor is that the hollow space located below the brakebeam 10 is covered outward by the side protection 12 sideward.

FIGS. 3a to 3c each show the operator platform 4 in a plan view withdifferent positions of the operator seat 6, said seat taking differentoperating positions 6 a, 6 b, 6 c. FIGS. 3a to 3c particularly show thatthe operator seat 6 both can be shifted to the sides of the platform 4,i.e., horizontally and transversely to the working direction A, and isalso mounted so as to be rotatable about a vertical axis. Here,operating positions 6 a, 6 b and 6 c merely show exemplary positionsamong a huge number of possible operating positions that can be taken bythe operator seat 6, which in the present exemplary embodiment can beadjusted essentially continuously between the two outer operatingpositions thereof, with FIG. 3a showing the left side operating positionwith an operator seat 6 rotated, and FIGS. 3b and 3c showing the leftside and the central operating position, respectively, with an operatorseat 6 in each case oriented in the forward or working direction A ofthe construction machine. Just as well, displacement of the operatorseat 6 to the right side of the platform 4 viewed in the workingdirection is possible (corresponding to the right side operatingposition), or a rotation of the operator seat 6 when in a positioncentral on the platform 4.

Due to is central arrangement on the platform 4 and its ergonomic shape,the brake beam 10 can be operated and comfortably reached by foot by themachine operator from all operating positions. Thus, flexibility inpositioning the operator seat 6 can be entirely exploited by the machineoperator, and he is not limited to a low number of actually possibleoperating positions by specifically assigned foot actuation devices withlimited accessibility, as they are known from the prior art. To thatend, the brake beam is designed as a beam-shaped element orientedhorizontally and, with its longitudinal extension transversely to theworking direction, said element having essentially the surface of arectangle, with the longitudinal sides being considerably longer thanthe face sides, i.e., in the present case preferably at least by thefactor 5. Furthermore, the width C of the brake beam extends acrossabout 80% of width B of the platform and thus continuously extendsacross the most part of the platform. This ensures that the operator iscapable of reaching the brake beam from the operator seat from a varietyof different adjustment positions of the operator seat.

Furthermore, the brake beam with its surface facing the operator isdesigned continuously and uniformly over its entire width (orientationtransversely to the working direction) in order to enable the sameoperating conditions across the entire width of the brake beam. Here,the term “continuous” should be understood such that the surface is notnecessarily designed in a closed fashion (although this is preferred),but forms a continuous operating surface for the foot of the operator.

FIG. 4 shows the operator platform 4 in a side view. Here, in particularthe region is emphasized in which the actuation device 9 with the brakebeam 10 is arranged. In order to allow a better view of the mechanics ofthe actuation device 9, illustration of the side protection 12 has beenomitted. The brake beam 10 is directly mounted on the platform base 8via the hinge 13, and, together with the base, forms the rotation angleα. The hinge 13 is protected upwards and toward the operator seat 6 bymeans of protection strip 11. An edge 19 of the brake beam which is benttwice by 90 degrees is located at the side of the brake beam 10 facingaway from the operator seat 19 such that the brake beam 10 has aU-shaped profile in this area. Just like the side protection 12, saidedge serves for separating the hollow space 20 below the brake beam 10and for protecting it against damage, for example, by dirt. At the sametime, the double-bent edge 19 forms a support or stop surface for thebrake beam 10 on the operator platform base 8.

The actuator 15, which can be seen in this view, is also arranged insidethe hollow space 20 below the brake beam 10. The brake beam 10 restswith its own weight on a roller 14 which is part of the actuator 15. Thedegree of freedom of the actuator 15 is determined by another hinge 17.Actuator 15 is loaded by a return spring for returning the brake beam 10to a rest position. By the tension of the spring 16, actuator 15 ispushed upwards, lifting the brake beam 10 in direction of its restposition as a result. Here, upwards movement of the brake beam 10 islimited by a stop trunnion 18 protruding beyond the brake beam 10.Therefore, in the rest position of brake beam 10 as shown in FIG. 4, thereturn spring 16 presses the brake beam 10 against the stop trunnion 18via the actuator 15.

FIG. 5 essentially illustrates the same regions as FIG. 4, with thedifference that that brake beam 10 is shown in a fully actuated positionhere, which may, for example, occur upon actuation by foot of themachine operator. If actuation surface 23 is pushed downwards by thefoot of a machine operator, brake beam 10 pivots downwards via the hinge13. As a result of the brake beam 10 being pushed downwards, actuator 15is pushed downwards as well and folds down via the hinge 17. Thisadditionally loads return spring 16 so that the effective spring forcepushing the brake beam 10 upwards is increased. However, rotation angleα is limited, as in case of the machine operator acting with excessiveforce the brake beam 10 stops with its lower surface, in particular withthe bent edge 19. This, when compared to the rest position of FIG. 4,maximally-hinged position of brake beam 10 is illustrated in FIG. 5.

FIG. 6 shows the actuation device 9 in a view from below, in particularrepresenting the area of actuator 15. In order to better visualize theactuator 15 here, illustration of the operator platform base has beenomitted. Actuator 15 comprises two curved discs 25 which are arranged inparallel and are connected to one another by an axle 26 and a hinge 17.Discs 25 are of semicircular geometry, with the circle center beinglocated on the elongated pivot axis W of hinge 17. A roller 24 is ineach case located on the upper end of discs 25, on which roller thebrake beam rests. In relation to the semicircular geometry of discs 25,axle 26 is arranged essentially opposite the rollers 14. It is loaded bymeans of the return springs 16, which are fixed behind the rollers 14relative to the platform base when viewed from axle 26. This way, thetension of the return springs 16 acting on the axle 26 is of an oppositeeffect to the load of rollers 24 by the weight of brake beam 10 and inparticular by an actuation by foot of brake beam 10. Actuator 15 thusforms a brake pedal about the hinge 17 or the pivot axis W, with theforce of the return springs 16 acting on the one side thereof and theweight force of brake beam 10 or weight force applied by the machineoperator acting on the other side. The rotation axis of roller 24 andthe pivot axis of brake beam 10 run parallel to one another. Uponactuation of brake beam 10, roller 24 thus rolls along the inner side ofbrake beam 10.

A lever 21 is arranged on one side of the parallel discs 25, said leverconnecting the actuator 15 with a rotation angle sensor 24. Lever 21 isconnected to disc 25 via a joint so that it is capable of rotatingdownwards and upwards, i.e., parallel to the extension of disc 25, aswell as to the left and to the right, i.e., perpendicularly to theextension of disc 25. If brake beam 10 is folded down via hinge 13,actuator 15 rotates about hinge 17 and thus pushes lever 21 towards therotation angle sensor 25. As the shank 27 of the rotation angle sensor24, on which lever 21 is mounted on the opposite side, is mounted to berotatable about an axis S running perpendicularly to the pivot axis W ofactuator 15, clockwise rotation of actuator 15 results in the lever 21rotating shank 27 about axis S in a direction away from actuator 15.Lever 21 folds to the outside on the joint, when viewed from disc 25.Said movement is effected by actuation of brake beam 10, for example. Inturn, a counter-clockwise rotation of actuator 15 causes the lever 21 tofold inwards to the disc 25 and the shank 27 to be rotated about theaxis S in a direction toward the actuator 15. This movement is effectedby returning brake beam 10 by means of the return springs 16, forexample. In both cases, rotation angle β of the shank 27 of the rotationangle sensor 24 changes at the same time. The rotation angle α of brakebeam 10 is thus translated via actuator 15 and lever 21 into rotationangle β of the shank 27 of the rotation angle sensor 24, which angle isthen measured by the rotation angle sensor 24 and then IT-processed inorder to control the brake assembly.

While the present invention has been illustrated by description ofvarious embodiments and while those embodiments have been described inconsiderable detail, it is not the intention of Applicants to restrictor in any way limit the scope of the appended claims to such details.Additional advantages and modifications will readily appear to thoseskilled in the art. The present invention in its broader aspects istherefore not limited to the specific details and illustrative examplesshown and described. Accordingly, departures may be made from suchdetails without departing from the spirit or scope of Applicants'invention.

What is claimed is:
 1. A construction machine, comprising: a brakeassembly for braking the construction machine, and an operator platformcomprising at least one operator seat that can be adjusted between atleast two opposite side operating positions for a machine operator, andan actuation device for foot actuation of the brake assembly, whereinthe actuation device for the brake assembly comprises a brake beam whichextends transversely to a working direction (A) of the constructionmachine on the operator platform and can be operated by foot from thetwo side operating positions, and that the actuation device comprises anactuator for the brake beam which is arranged below the brake beam. 2.The construction machine according to claim 1, wherein a surface of thebrake beam facing the operator seat is configured as a continuousactuation surface.
 3. The construction machine according to claim 1,wherein the operator platform includes an operator platform base, andthat the brake beam is pivotally mounted on the platform base.
 4. Theconstruction machine according to claim 3, wherein the actuation devicecomprises a joint protection which is arranged above the joint.
 5. Theconstruction machine according to claim 1, wherein an edge of the brakebeam facing away from the operator seat is bent downward.
 6. Theconstruction machine according to claim 3, wherein a transmissionmechanism for the actuator is provided, said transmission mechanismbeing entirely covered upward by the brake beam and the platform base inthe region of the operator platform.
 7. The construction machineaccording to claim 1, wherein the actuation device comprises a returnspring, and the actuator is loaded by the return spring in such a waythat if the brake beam is not actuated, the brake beam is automaticallyreturned to a rest position by means of the return spring.
 8. Theconstruction machine according to claim 7, wherein the actuation devicecomprises a spring break sensor which is configured to detect a springbreak of the return spring of the brake beam, the spring break sensorbeing arranged in particular below the brake beam.
 9. The constructionmachine according to claim 1, wherein the actuator is centrally arrangedwith respect to an extension of the brake beam along a longitudinalcentral axis of the brake beam.
 10. The construction machine accordingto claim 1, wherein the actuator comprises a roller via which the brakebeam rests on the actuator, in particular such that the lower side ofthe brake beam forms a rolling surface for the roller.
 11. Theconstruction machine according to claim 1, wherein the actuator of thebrake beam is configured as a brake pedal, the brake pedal beingarranged such that it is pivotable about an axis (W) between a maximallyactuated position and a non-actuated position.
 12. The constructionmachine according to claim 1, wherein the actuator of the brake beam ismechanically connected to an electric, hydraulic or pneumatic brakevalve.
 13. The construction machine according to claim 1, wherein theactuation device comprises a side protection which is arranged on a sideof the brake beam facing away from the operator seat and is configuredto seal a hollow space below the brake beam toward said side.
 14. Theconstruction machine according to claim 3, wherein the actuation devicecomprises a rotation angle sensor which is arranged below the brake beamor below the platform base and which is configured to determine arotation angle (α) of the brake beam.
 15. The construction machineaccording to claim 1, wherein the brake assembly is part of a brakesystem of the construction machine and is configured as an operatingbrake.
 16. The construction machine according to claim 1, wherein theoperator seat comprises at least one of the following features: theoperator seat is configured as a rotatable operator seat, the operatorseat is configured as a laterally displaceable operator seat, theoperator seat is arranged on a laterally displaceable seat support, orthe operator seat is arranged relative to the brake beam in such a waythat the brake beam is located within the comfort region of the seatedmachine operator, said region defined by the DIN EN ISO 6682:2009-06standard for foot-actuatable controls in earth moving machines.
 17. Theconstruction machine according to claim 1, wherein the constructionmachine is configured as a road finisher, a soil compactor or arubber-tired roller.
 18. The construction machine according to claim 2,wherein the actuation surface comprises an anti-slip coating.
 19. Theconstruction machine according to claim 3, wherein the joint is formedas at least one hinge.
 20. The construction machine according to claim15, wherein the brake system comprises a second brake assembly.
 21. Theconstruction machine according to claim 15, wherein the operating brakecomprises one of a disk brake, a drum brake or a multi-disk brake andsaid second brake assembly is configured as a hydrostatic brakeassembly.